[mypy] Enable following imports for entrypoints (#7248)

Co-authored-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>
Co-authored-by: Fei <dfdfcai4@gmail.com>

docs/requirements-docs.txt

@@ -6,7 +6,7 @@ sphinx-argparse==0.4.0
 msgspec
 
 # packages to install to build the documentation
-pydantic
+pydantic >= 2.8
 -f https://download.pytorch.org/whl/cpu
 torch
 py-cpuinfo